Cooling system and method for a high-temperature ammonia injection denitration water-cooled spray gun

Abstract

The present invention discloses a cooling system and method for a high-temperature ammonia injection denitration water-cooled spray gun. By sleeving a water-cooling jacket on the surface of the spray gun to form a water-cooling cavity, and at the same time arranging a reverse return channel in some areas where the spray gun extends into the boiler to perform secondary cooling treatment on the spray gun, and an outwardly convex cooling water spray nozzle is arranged at the end of the reverse return channel to cool the surface of the cooling structure; due to the heat conduction effect in the part of the spray gun outside the boiler, the temperature inside the water-cooling jacket rises. An air-cooling structure is sleeved on the surface of the water-cooling jacket to cool this area, avoiding the problem that the cooling water does not enter the boiler interior and heats up due to the direct contact between the water-cooling jacket and the boiler side wall, thereby improving the cooling efficiency. An air-cooling spray nozzle is arranged on the side wall of the air-cooling structure to cool the surface of the cooling structure between the air-cooling spray nozzle and the outwardly convex water-cooling spray nozzle. The present invention can efficiently improve the cooling effect, and specifically adopt the cooperation of water cooling and air cooling for different cooling areas, greatly improving the cooling effect.

Description

Technical Field

[0001] The present invention relates to a coal-fired boiler spray gun, specifically to a cooling system and method for a high-temperature ammonia injection denitration water-cooled spray gun. Background Art

[0002] In recent years, the proportion of coal in China's total energy consumption has been increasing year by year. NOx is one of the main pollutants formed during the combustion of coal, which seriously affects the environment, climate and human health. With the growth of the total NOx emissions and the improvement of environmental protection requirements, effective denitration technologies need to be developed to control NOx emissions. Ammonia injection reduction of NOx in the fuel-rich zone is a denitration method that utilizes the reduction effect of NH3 on NOx in a fuel-rich environment.

[0003] Compared with the SCR technology, the high-temperature ammonia injection technology in the fuel-rich zone does not require the use of catalysts, and the investment and maintenance costs are greatly reduced; compared with the SNCR technology, since the amino reducing agent is injected in a fuel-rich and oxygen-deficient environment, there is no condition for the oxidation of NH3, and the utilization rate of the reducing agent is high.

[0004] However, this technology has high requirements for the injection conditions of the amino reducing agent and requires a high-temperature and oxygen-free environment, and existing equipment is difficult to meet the usage requirements. Because when the existing spray gun covers the reducing agent in the boiler, it is affected by the temperature rise and cannot operate for a long time at high temperature. Summary of the Invention

[0005] Aiming at the problem that the existing spray gun cannot operate in the high-temperature environment inside the boiler for a long time, the present invention provides a cooling system and method for a high-temperature ammonia injection denitration water-cooled spray gun.

[0006] The present invention is realized through the following technical solutions:

[0007] A cooling system for a high-temperature ammonia injection denitration water-cooled spray gun includes a spray gun, a water-cooling jacket and an air-cooling jacket; one end of the spray gun extending into the boiler is provided with a spray gun head, and a reducing agent interface is provided on the side wall of the other end located outside the boiler; the outer wall of the spray gun rod between the spray gun head and the reducing agent interface is sleeved with the water-cooling jacket, and a water-cooling cavity is formed; one side wall of the water-cooling jacket at the outer side of the boiler is provided with a cooling water interface, and the other end covers the outside of the spray gun head and is provided with a communicating reverse folding channel on the outside, and a plurality of outwardly convex water-cooling spray heads are provided at the end of the reverse folding channel; the air-cooling jacket is sleeved outside the water-cooling jacket to form an air-cooling cavity, the air-cooling jacket is located in the area where it meets the boiler, and one end is arranged outside the boiler and the other end is flush with the inner wall of the boiler; one end of the air-cooling cavity on the outer wall of the boiler is provided with a cooling air interface, and a plurality of air-cooling spray heads are provided at the end flush with the inner wall of the boiler.

[0008] Further, a thermocouple induction end is provided at the gun head of the spray gun, and a thermocouple lead-out end is provided at the tail of the spray gun, forming a temperature detection unit for the gun head of the spray gun.

[0009] Further, the nozzle directions of the convex water-cooled nozzle and the air-cooled nozzle are parallel to the spray gun.

[0010] Further, the nozzle directions of the convex water-cooled nozzle and the air-cooled nozzle are both set towards the direction of the gun head of the spray gun.

[0011] Further, the convex structure of the convex water-cooled nozzle is vertically arranged in the direction of the gun barrel of the spray gun.

[0012] Further, an insulating paint coating layer is applied to the outer wall of the area where the spray gun is wrapped by the water-cooling jacket.

[0013] Further, fixing members are provided on the outer wall of the air-cooling jacket.

[0014] Further, the fixing members are fixedly connected to the pipe socket on the boiler through flange plates and fastening screws.

[0015] A cooling method for a high-temperature ammonia injection denitration water-cooled spray gun of a coal-fired boiler includes the following steps:

[0016] Cooling water enters the water-cooling cavity through the cooling water interface, cools the surface of the spray gun, enters the reverse folding channel at the gun head of the spray gun, and sprays out from the convex water-cooled nozzle at the end of the reverse folding channel to cool the surface of the water-cooling jacket.

[0017] Cooling air enters the air-cooling cavity through the cooling air interface to cool the area of the boiler side wall in contact, and at the same time, the air-cooled nozzle sprays out cooling air to cool the area from the air-cooled nozzle to the convex water-cooled nozzle.

[0018] Further, the thermocouple induction end senses the temperature of the spray gun nozzle, transmits it back to the thermocouple contact end, and controls the flow rates of the cooling air and the cooling water.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention provides a cooling system for a high-temperature ammonia spray denitrification water-cooled spray gun. First, a water-cooling jacket is sheathed on the surface of the spray gun to form a water-cooling cavity. At the same time, a reverse return channel is provided in the partial area where the spray gun extends into the interior of the boiler, so that the spray gun can be subjected to secondary cooling treatment. An outwardly convex cooling water nozzle is provided at the end of the reverse return channel to cool the surface of the cooling structure. Secondly, the spray gun is subjected to the heat conduction effect on the outer part of the boiler, which causes the internal temperature of the water-cooling jacket to increase. Therefore, an air-cooling structure is sheathed on the surface of the water-cooling jacket to cool this area, and avoids the problem that the cooling water does not enter the boiler interior and heats up due to direct contact between the water-cooling jacket and the side wall of the boiler, thereby improving the cooling efficiency. An air-cooling nozzle is provided on the side wall of the air-cooling structure, which can cool the surface of the cooling structure between the air-cooling nozzle and the outwardly convex water-cooling nozzle. The cooling system has a simple structure, but can efficiently improve the cooling effect, and adopts water cooling and air cooling in a targeted manner for different cooling zones, thereby greatly improving the cooling effect.

[0021] Furthermore, in the present invention, the outer wall of the spray gun pipe inside the water-cooling cavity is coated with oil insulating paint to reduce the heat exchange between the cooling air and the reducing agent.

[0022] Furthermore, a thermocouple sensing end is provided inside the spray gun nozzle at one end of the spray gun pipe of the present invention, and a thermocouple output end is provided at the other end, which is used to sense the temperature of the nozzle so as to control the flow rate of the cooling air, so as to keep the nozzle at a low temperature while minimizing the amount of cooling air and cooling water, thereby reducing the impact on boiler combustion.

[0023] This invention provides a cooling method for a high-temperature ammonia denitrification water-cooled spray gun. Cooling water enters a cooling cavity to cool the spray gun surface. When the cooling water exits the spray gun end, it enters a reverse channel, dissipating heat again to lower the temperature of this area. The water is then ejected through an outward-facing water-cooling nozzle to cool the water-cooling jacket. Simultaneously, cooling air enters an air-cooling structure to cool the water-cooling jacket outside the boiler before being ejected through the air-cooling nozzle to further cool the water-cooling jacket inside the boiler. This method utilizes a combination of water and air cooling in targeted areas, significantly improving the cooling effect.

[0024] Furthermore, the thermocouple sensing end senses the temperature of the nozzle in real time, and feeds back and controls the flow of cooling air through the thermocouple output end, so as to keep the nozzle low in temperature while minimizing the amount of cooling air and cooling water, thereby reducing the impact on boiler combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a cooling system for a high-temperature ammonia spray denitrification water-cooled spray gun in a specific embodiment of the present invention;

[0026] Figure 2Schematic diagram of the structure outside the boiler of the cooling system of a high-temperature ammonia injection denitration water-cooled spray gun in a specific embodiment of the present invention;

[0027] Figure 3a Schematic diagram of the end structure of the cooling system of a high-temperature ammonia injection denitration water-cooled spray gun in a specific embodiment of the present invention;

[0028] Figure 3b Schematic cross-sectional view of the end structure of the cooling system of a high-temperature ammonia injection denitration water-cooled spray gun in a specific embodiment of the present invention.

[0029] In the figure: spray gun 1; water-cooling jacket 2; air-cooling jacket 3; fixing part 4; spray gun head 11; thermocouple induction end 12; thermocouple lead-out end 13; insulating paint coating 14; reducing agent interface 15; water-cooling cavity 21; cooling water interface 22; reverse-fold channel 23; outward-convex water-cooling nozzle 24; air-cooling cavity 31; air-cooling nozzle 32; cooling air interface 33. Detailed implementation manners

[0030] The following further describes the present invention in detail with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0031] The present invention provides a specific embodiment of a cooling system for a high-temperature ammonia injection denitration water-cooled spray gun. As shown in FIG. 1, it includes a spray gun 1, a water-cooling jacket 2, and an air-cooling jacket 3. Among them, one end of the spray gun 1 is a spray gun head 11, which is located inside the boiler, and the other end side wall is provided with a reducing agent interface 15, which is located outside the boiler. The outer wall of the spray gun rod between the spray gun head 11 and the reducing agent interface 15 is sleeved with a water-cooling jacket 2, and a water-cooling cavity 21 is formed;

[0032] Among them, one end side wall of the water-cooling jacket 2 is provided with a cooling water interface 22, and the other end is provided with a reverse-fold channel 23 near the spray gun head 11, covering and wrapping the part of the water-cooling jacket 2 located inside the boiler, forming protection for the cooling medium inside the water-cooling jacket 2 in this area, avoiding the problem of low cooling efficiency caused by direct contact, and the end of the reverse-fold channel 23 is multiple outward-convex water-cooling nozzles 24, as Figure 3a shown in FIGS. 3a and 3b. Specifically, the outward-convex water-cooling nozzle 24 can be an outward-convex structure perpendicular to the spray gun rod direction, and can also be arranged at other angles with respect to the spray gun rod direction. Its purpose is to carry and protect the internal nozzle;

[0033] As Figure 2 shown, the air-cooling jacket 3 is sleeved outside the water-cooling jacket 2 to form an air-cooling cavity 31. The air-cooling jacket 3 is located in the area where it intersects with the boiler and outside the boiler. One end of the air-cooling cavity 31 facing the inside of the boiler is provided with multiple air-cooling nozzles 32, and the other end of the air-cooling cavity 31 is provided with a cooling air interface 33.

[0034] Furthermore, a thermocouple sensing end 12 is provided at the gun head 11 of the spray gun, and a thermocouple lead-out end 13 is provided at the tail of the spray gun 1, forming a temperature detection unit for the gun head of the spray gun to sense the temperature of the nozzle, so as to control the flow rate of the cooling air, keep the nozzle at a low temperature, and minimize the cooling air and the amount of cooling water as much as possible, thereby reducing the impact on the internal temperature of the boiler.

[0035] The nozzle directions of the convex water-cooled nozzle 24 and the air-cooled nozzle 32 are parallel to the spray gun 1, and the nozzle directions of the convex water-cooled nozzle 24 and the air-cooled nozzle 32 are both set towards the direction of the gun head 11 of the spray gun, which can cool down the side wall of the spray gun rod, minimize the impact of the sprayed cooling medium on the internal temperature of the boiler, and at the same time cooperate with the multiple convex water-cooled nozzles 24 at the end of the reverse folding channel 23 to improve the cooling efficiency of the entire side wall of the spray gun rod inside the boiler. Since the temperature in the boiler side wall area is relatively low and the impact on the internal temperature of the boiler during cooling needs to be reduced, the water-cooled cavity 21 in the boiler side wall area is air-cooled, and the water-cooled cavity 21 on the side wall of the gun rod in the boiler internal area needs to use water-cooling to form a segmented cooling effect.

[0036] Specifically, an insulating paint coating layer 14 is applied to the outer wall of the area of the spray gun 1 wrapped by the water-cooling sleeve 2 to reduce the heat exchange between the cooling air and the reducing agent, thereby improving the cooling heat conversion rate of the cooling medium.

[0037] Specifically, the air-cooling sleeve 3 is provided with a fixing member 4, and the fixing member 4 is vertically arranged on the outer wall of the air-cooling sleeve 3. The fixing member 4 is fixedly connected to the pipe seat on the boiler through a flange and a fastening screw to position the spray gun 1 and the cooling device, which is easy to install and maintain.

[0038] A cooling method for a high-temperature ammonia injection denitration water-cooled spray gun of the present invention includes the following steps:

[0039] Cooling water enters the water-cooled cavity 21 through the cooling water interface 22 to cool down the surface of the spray gun 1, enters the reverse folding channel 23 at the gun head 11 of the spray gun, and is sprayed out from the convex water-cooled nozzle 24 at the end of the reverse folding channel 23 to cool down the surface of the water-cooling sleeve 2. At the same time, in the reverse folding channel 23, the water-cooled cavity 21 in the covered area is cooled down, and at the same time, it is prevented from being directly heated by the boiler;

[0040] Cooling air enters the air-cooled cavity 31 through the cooling air interface 33 to cool down the contacted boiler side wall area. At the same time, the air-cooled nozzle 32 sprays out cooling air to cool down the area from the air-cooled nozzle 32 to the convex water-cooled nozzle 24.

[0041] Cooling water enters the cooling cavity to cool the surface of the spray gun. When the cooling water exits at the end of the spray gun and enters the reverse folding channel 23, it dissipates heat again to reduce the temperature of this area, and then is sprayed out through the convex water-cooled nozzle 24 to cool the water-cooled jacket 2; at the same time, cooling air enters the air-cooling structure, cools the water-cooled jacket 2 outside the boiler, and then is sprayed out through the air-cooling nozzle to cool the water-cooled jacket 2 inside the boiler again, forming a segmented cooling of the water-cooled cavity 21 on the side wall of the spray gun inside the boiler. This method uses water cooling and air cooling in combination for different cooling zones, greatly improving the cooling effect.

[0042] At the same time, the thermocouple sensing end 12 senses the temperature of the nozzle in real time, and feeds back and controls the flow rate of the cooling air through the thermocouple output end 13, so that while keeping the spray gun nozzle 11 at a low temperature, the amount of cooling air and cooling water is minimized, thereby reducing the impact on boiler combustion.

Claims

1. A cooling system for a high-temperature ammonia injection denitration water-cooled spray gun, characterized in that, It includes a spray gun (1), a water-cooling jacket (2) and an air-cooling jacket (3); One end of the spray gun (1) extending into the boiler is provided with a spray gun tip (11), and a reducing agent interface (15) is arranged on the side wall of the other end located outside the boiler; the outer wall of the spray gun rod between the spray gun tip (11) and the reducing agent interface (15) is sleeved with a water-cooling jacket (2), and a water-cooling cavity (21) is formed; One side wall of the water-cooling jacket (2) at the end outside the boiler is provided with a cooling water interface (22), the other end covers and is arranged outside the spray gun tip (11), and a communicating reverse folding channel (23) is arranged on the outside, and a plurality of outwardly convex water-cooling nozzles (24) are arranged at the end of the reverse folding channel (23); the cooling water enters the water-cooling cavity (21) through the cooling water interface (22) to cool the surface of the spray gun (1), enters the reverse folding channel (23) at the spray gun tip (11), and is sprayed out from the outwardly convex water-cooling nozzles (24) at the end of the reverse folding channel (23) to cool the surface of the water-cooling jacket (2); The air-cooling jacket (3) is sleeved outside the water-cooling jacket (2) to form an air-cooling cavity (31). The air-cooling jacket (3) is located in the area where it meets the boiler, and one end is arranged outside the boiler, and the other end is flush with the inner wall of the boiler; One end of the air-cooling cavity (31) on the outer wall of the boiler is provided with a cooling air interface (33), and a plurality of air-cooling nozzles (32) are arranged at the end flush with the inner wall of the boiler; the cooling air enters the air-cooling cavity (31) through the cooling air interface (33) to cool the area of the boiler side wall it contacts. At the same time, the air-cooling nozzles (32) spray out cooling air to cool the area from the air-cooling nozzles (32) to the outwardly convex water-cooling nozzles (24); The spray gun tip (11) is provided with a thermocouple induction end (12), and the tail of the spray gun (1) is provided with a thermocouple lead-out end (13) to form a spray gun tip temperature detection unit; The outer wall of the area where the spray gun (1) is wrapped by the water-cooling jacket (2) is coated with an insulating paint coating (14).

2. The cooling system of a high-temperature ammonia injection denitration water-cooled spray gun according to claim 1, wherein, The spraying directions of the outwardly convex water-cooling nozzles (24) and the air-cooling nozzles (32) are parallel to the spray gun (1).

3. The cooling system of a high-temperature ammonia injection denitration water-cooled spray gun according to claim 1, characterized in that, The spraying directions of the outwardly convex water-cooling nozzles (24) and the air-cooling nozzles (32) are both set in the direction of the spray gun tip (11).

4. The cooling system of a high-temperature ammonia injection denitration water-cooled spray gun according to claim 1, characterized in that, The outwardly convex structure of the outwardly convex water-cooling nozzles (24) is vertically arranged in the direction of the spray gun rod.

5. The cooling system of a high-temperature ammonia injection denitration water-cooled spray gun according to claim 1, characterized in that, A fixing member (4) is arranged on the outer wall of the air-cooling jacket (3).

6. The cooling system of a high-temperature ammonia injection denitration water-cooled spray gun according to claim 5, characterized in that, The fixing member (4) is fixedly connected to the pipe seat on the boiler through a flange and a fastening screw.

7. A cooling method for a water-cooled spray gun for high-temperature ammonia injection denitration, characterized in that, Based on any one of the cooling systems of the high-temperature ammonia injection denitration water-cooled spray gun according to claims 1-6, it includes the following steps: The cooling water enters the water-cooling cavity (21) through the cooling water interface (22) to cool the surface of the spray gun (1), enters the reverse folding channel (23) at the spray gun tip (11), and is sprayed out from the outwardly convex water-cooling nozzles (24) at the end of the reverse folding channel (23) to cool the surface of the water-cooling jacket (2); The cooling air enters the air-cooling cavity (31) through the cooling air interface (33) to cool the area of the boiler side wall it contacts. At the same time, the air-cooling nozzles (32) spray out cooling air to cool the area from the air-cooling nozzles (32) to the outwardly convex water-cooling nozzles (24); The thermocouple sensing end (12) senses the temperature of the spray gun tip (11), transmits it back to the thermocouple connection end (13), and controls the flow rates of the cooling air and the cooling water.

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